Particle removing assembly and method of cleaning mask for lithography

ABSTRACT

An photolithographic apparatus includes a particle removing cassette selectively extendable from the processing apparatus. The particle removing cassette includes a wind blade slit and an exhausting slit. The wind blade slit is configured to direct pressurized cleaning material to a surface of the mask to remove the debris particles from the surface of the mask. The exhausting slit collects the debris particles separated from the surface of the mask and contaminants through the exhaust line. In some embodiments, the wind blade slit includes an array of wind blade nozzles spaced apart within the wind blade slit. In some embodiments, the exhausting slit includes array of exhaust lines spaced apart within the exhausting slit.

PRIORITY CLAIM AND CROSS-REFERENCE

This application claims priority to U.S. application Ser. No. 17/085,206filed on Oct. 30, 2020, now U.S. Pat. No. 11,294,292, which claimspriority to U.S. Provisional Application No. 62/955,351 filed on Dec.30, 2019, the entire disclosure of both applications are incorporatedherein by reference.

BACKGROUND

Debris particles can reduce the yield of photolithography operations byundesirably shielding portions of a mask pattern. It is, therefore,desirable to maintain a clean environment in locations and routes wheremasks pass through during the lithography process such as tool grippers,chambers, mask holders, etc. In particular, the ability to produce highquality microelectronic devices and reduce yield losses is dependentupon maintaining the surfaces of critical components substantiallydefect-free. This would include maintaining the surfaces free ofcontaminants, e.g., maintaining an ultra-clean surface ensuring thatcontaminants are not deposited on the surface of the wafer, the reticleor mask or other critical components. This is of particular concern asfiner features are required on the microelectronic device. The types ofcontaminants can be any arbitrary combination depending on theenvironment and the vacuum condition. The contaminants could beintroduced from operations, such as etching byproducts in the maskmaking process, organic hydrocarbon contaminants, any kind of fall-ondust, outgassing from steel, and so on.

Photolithographic equipment is cleaned using a vacuum and an isopropylalcohol/ethanol wipe-down, and particle counters are used to monitor andverify cleanliness. However, such manual cleaning may not be preferablefor vacuum chambers. Moreover, wipe-down and/or vacuum cleaning ofdelicate or small components is not desirable. Additionally, theseprocedures are not specific to locations and routes through which maskswould pass or potentially get contaminated. Thus, alternate methods ofmaintaining cleanliness of the masks are desirable.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is best understood from the following detaileddescription when read with the accompanying figures. It is emphasizedthat, in accordance with the standard practice in the industry, variousfeatures are not drawn to scale and are used for illustration purposesonly. In fact, the dimensions of the various features may be arbitrarilyincreased or reduced for clarity of discussion.

FIG. 1 shows a schematic view of a semiconductor wafer processingsystem, in accordance with some embodiments.

FIGS. 2A, 2B, 2C, 2D, and 2E show a schematic diagram of a semiconductorwafer process according to an embodiment of the disclosure.

FIG. 3 shows an embodiment for removing debris particles.

FIGS. 4A and 4B show detailed views of a particle removing assemblyaccording to an embodiment of the disclosure.

FIGS. 5A and 5B show detailed views of a particle removing cassetteselectively extendable from the photolithographic apparatus according toan embodiment of the disclosure.

FIGS. 6A and 6B, show detailed views of an array of particle removingnozzles according to the present disclosure.

FIG. 7 shows a detailed view of a system for particle removing andinspecting according to an embodiment of the disclosure.

FIG. 8 shows a detailed view of a particle removing assembly accordingto another embodiment of the disclosure.

FIGS. 9A, 9B, 9C, 9D, 9E, 9F, 9G, and 9H show a method cleaning a maskfor photolithographic apparatus according to an embodiment of thedisclosure.

DETAILED DESCRIPTION

It is to be understood that the following disclosure provides manydifferent embodiments, or examples, for implementing different featuresof the disclosure. Specific embodiments or examples of components andarrangements are described below to simplify the present disclosure.These are, of course, merely examples and are not intended to belimiting. For example, dimensions of elements are not limited to thedisclosed range or values, but may depend upon process conditions and/ordesired properties of the device. Moreover, the formation of a firstfeature over or on a second feature in the description that follows mayinclude embodiments in which the first and second features are formed indirect contact, and may also include embodiments in which additionalfeatures may be formed interposing the first and second features, suchthat the first and second features may not be in direct contact. Variousfeatures may be arbitrarily drawn in different scales for simplicity andclarity.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The device may be otherwise oriented (rotated 90 degrees orat other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly. In addition, the term“made of” may mean either “comprising” or “consisting of.”

The present disclosure relates to a contaminant particle removingcassette that is designed to remove contaminants to improve cleanlinessof masks.

As the semiconductor industry has progressed into nanometer technologyprocess nodes in pursuit of higher device density, higher performance,and lower costs, there have been challenges in reducing semiconductorfeature size. Extreme ultraviolet lithography (EUVL) has been developedto form smaller semiconductor device feature size and increase devicedensity on a semiconductor wafer. In order to improve EUVL, an increasein wafer exposure throughput is desirable. Wafer exposure throughput canbe improved through increased exposure power or increased resistphotospeed (sensitivity).

Metal-containing photoresists are used in extreme ultraviolet (EUV)lithography because metals have a high absorption capacity of extremeultraviolet radiation and thus increase the resist photospeed.Metal-containing photoresist layers, however, may outgas duringprocessing which can cause the photoresist layer quality to change overtime and may cause contamination, thereby negatively affectinglithography performance and increasing defects.

FIG. 1 is a schematic view of a semiconductor wafer processing system,in accordance with some embodiments. In some embodiments, thesemiconductor wafer processing system includes a processing apparatus10, a load lock chamber 20, a pressure adjusting module 30, an interfacemodule 40, one or more load ports 50, one or more carriers 60, and acontroller 70, in accordance with some embodiments. It should beappreciated that the features described below can be replaced oreliminated in other embodiments of the semiconductor wafer processingsystem.

In some embodiments, the processing apparatus 10 includes a light source11, an illuminator 12, a mask stage 13, a mask 14, a projection opticsmodule 15, a substrate stage 16, and a wafer transfer member 17, inaccordance with some embodiments. The elements of the processingapparatus 10 can be added to or omitted, and the disclosure should notbe limited by the embodiment.

The light source 11 is configured to generate radiation having awavelength ranging between about 1 nm and about 300 nm in someembodiments. In one particular example, the light source 11 generatesEUV light with a wavelength centered at about 13.5 nm. Accordingly, thelight source 11 is also referred to as an EUV light source in someembodiments. However, it should be appreciated that the light source 11should not be limited to emitting EUV light. The light source 11 can bethe other light sources including deep UV, such as an ArF or KrF laser.

In various embodiments, the illuminator 12 includes various refractiveoptic components, such as a single lens or a lens system having multiplelenses (zone plates) or alternatively reflective optics (for EUVlithography system), such as a single mirror or a mirror system havingmultiple mirrors in order to direct light from the light source 11 ontoa mask stage 13, particularly to the mask 14 secured on the mask stage13. In the present embodiment where the light source l lgenerates lightin the EUV wavelength range, reflective optics are employed.

The mask stage 13 is configured to secure the mask 14. In someembodiments, the mask stage 13 includes an electrostatic chuck (e-chuck)to secure the mask 14. This is because the gas molecules absorb EUVlight and the lithography system for the EUV lithography patterning ismaintained in a vacuum environment to avoid EUV intensity loss. In thepresent disclosure, the terms mask and reticle are used interchangeably.

In the present embodiment, the mask 14 is a reflective mask. Oneexemplary structure of the mask 14 includes a substrate with a suitablematerial, such as a low thermal expansion material (LTEM) or fusedquartz. In various examples, the LTEM includes TiO₂ doped SiO₂, or othersuitable materials with low thermal expansion. The mask 14 includesmultiple reflective multiple layers (ML) deposited on the substrate. TheML includes a plurality of film pairs, such as molybdenum-silicon(Mo/Si) film pairs (e.g., a layer of molybdenum above or below a layerof silicon in each film pair). Alternatively, the ML may includemolybdenum-beryllium (Mo/Be) film pairs, or other suitable materialsthat are configurable to highly reflect the EUV light.

The mask 14 may further include a capping layer, such as ruthenium (Ru),disposed on the ML for protection. The mask 14 further includes anabsorption layer, such as a tantalum boron nitride (TaBN) layer,deposited over the ML. The absorption layer is patterned to define alayer of an integrated circuit (IC). Alternatively, another reflectivelayer may be deposited over the ML and is patterned to define a layer ofan integrated circuit, thereby forming an EUV phase shift mask.

The projection optics module (or projection optics box (POB)) 15 isconfigured for imaging the pattern of the mask 14 onto a semiconductorwafer 5 secured on a substrate stage 16 of the processing apparatus 10.In some embodiments, the POB 15 has refractive optics (such as for a UVlithography system) or alternatively reflective optics (such as for anEUV lithography system) in various embodiments. The light directed fromthe mask 14, carrying the image of the pattern defined on the mask, iscollected by the POB 15. The illuminator 12 and the POB 15 arecollectively referred to as an optical module of the processingapparatus 10.

The wafer transfer member 17 is configured to deliver the semiconductorwafer 5 from one location within the processing apparatus 10 to another.For example, the semiconductor wafer 5 located in the load lock chamber20 is transferred to the substrate stage 16 by the wafer transfer member17. A radial and rotational movement of the wafer transfer member 17 canbe coordinated or combined in order to pick up, transfer, and deliverthe semiconductor wafer 5.

In the present embodiment, the semiconductor wafer 5 may be made ofsilicon or other semiconductor materials. Alternatively or additionally,the semiconductor wafer 5 may include other elementary semiconductormaterials such as germanium (Ge). In some embodiments, the semiconductorwafer 5 is made of a compound semiconductor such as silicon carbide(SiC), gallium arsenic (GaAs), indium arsenide (InAs), or indiumphosphide (InP). In some embodiments, the semiconductor wafer 5 is madeof an alloy semiconductor such as silicon germanium (SiGe), silicongermanium carbide (SiGeC), gallium arsenic phosphide (GaAsP), or galliumindium phosphide (GaInP). In some other embodiments, the semiconductorwafer 5 may be a silicon-on-insulator (SOI) or a germanium-on-insulator(GOI) substrate.

In addition, the semiconductor wafer 5 may have various device elements.Examples of device elements that are formed in the semiconductor wafer 5include transistors (e.g., metal oxide semiconductor field effecttransistors (MOSFET), complementary metal oxide semiconductor (CMOS)transistors, bipolar junction transistors (BJT), high voltagetransistors, high-frequency transistors, p-channel and/or n-channelfield-effect transistors (PFETs/NFETs), etc.), diodes, and/or otherapplicable elements. Various processes are performed to form the deviceelements, such as deposition, etching, implantation, photolithography,annealing, and/or other suitable processes.

In some embodiments, the semiconductor wafer 5 is coated with a resistlayer that is sensitive to EUV light. Various components including thosedescribed above are integrated together and are operable to perform thelithographic exposing operations.

It should be appreciated that while the processing apparatus 10 is alithography module, the embodiments of the disclosure should not belimited thereto. The processing apparatus 10 may be configured toperform any manufacturing procedure on a semiconductor wafer 5. Forexample, the processing apparatus 10 may be configured to performmanufacturing procedures that include deposition processes such asphysical vapor deposition (PVD), chemical vapor deposition (CVD),plasma-enhanced chemical vapor deposition (PECVD) and/or otherdeposition processes. Alternatively, the processing apparatus 10 may beconfigured to perform manufacturing procedures that include etchingprocesses such as wet etching, dry etching or ion beam milling. Also,the processing apparatus 10 may be configured to perform manufacturingprocedures that include lithographic exposure, ion implantation, thermalprocesses, cleaning processes, testing, any procedure involved in theprocessing of the semiconductor wafer 5, and/or any combination of suchprocedures.

The load lock chamber 20 is arranged between the processing apparatus 10and the interface module 40. The load lock chamber 20 is configured topreserve the atmosphere within the processing apparatus 10 by separatingit from the interface module 40. In some embodiments, the load lockchamber 20 includes a wafer stage 21, an external door 22 and aninterior door 23. When the semiconductor wafer 5 is inserted into theload lock chamber 20, the semiconductor wafer 5 is placed on the waferstage 21, and the external door 22 and the interior door 23 are sealed.As a result, an air-tight environment is built in the load lock chamber20.

The load lock chamber 20 is capable of creating an atmosphere compatiblewith the processing apparatus 10 or the interface module 40 depending onwhere the loaded semiconductor wafer 5 is scheduled to be next. This canbe performed by altering the gas content of the load lock chamber 20 byadding gas or creating a vacuum, along with other suitable means, usingsuch mechanisms as the pressure adjusting module 30, for adjustingatmosphere in the load lock chamber 20. When the correct atmosphere hasbeen reached, the semiconductor wafer 5 can be accessed.

The pressure adjusting module 30 is configured to reduce the pressure ofgas in the load lock chamber 20. In some embodiments, the pressureadjusting module 30 includes a gas tank 310 and a pumping assembly 32.In some embodiments, the volume of the gas tank 310 is greater than thevolume of a space defined in the load lock chamber 20 for receiving thesemiconductor wafer 5. In some embodiments, the volume of the gas tank310 is about 15 to about 20 times the volume of the load lock chamber20. As such, a pressure drop occurs in the load lock chamber 20, when alow pressure gas is contained in the gas tank 310 and an exchange of gasbetween the gas tank and the load lock chamber 20 is enabled.

In some embodiments, the gas tank 310 is connected to the load lockchamber 20 via the gas line 311. A valve 312 is positioned on the gasline 311 for controlling the flow of gas in the gas line 311. Inaddition, the gas tank 310 is connected to the pumping assembly 32 viathe gas line 313. A valve 314 is positioned on the gas line 313 forcontrolling the flow of gas in the gas line 313. Moreover, the pumpingassembly 32 is connected to the load lock chamber 20 via a gas line 24.A valve 25 is connected to the gas line 24 for controlling the flow ofgas in the gas line 24.

In some embodiments, the interface module 40 is a facility interface. Insome embodiments, the load port 50 is adjacent to the interface module40. In some embodiments, an overhead hoist transport (OHT) (not shown)transports the carrier 60, such as a standard mechanical interface(SMIF) or a front opening unified pod (FOUP) with the semiconductorwafer 5 from a stocker (not shown) to the load port 50.

In some embodiments, the interface module 40 includes a wafer transfermember 42 for delivering the semiconductor wafer 5 from one locationwithin the processing interface module 40 to another. For example, whenthe carrier 60 is located on the load port 50, the semiconductor wafer 5in the carrier 60 is transferred to the load lock chamber 20 by thewafer transfer member 42. A radial and rotational movement of the wafertransfer member 42 can be coordinated or combined in order to pick up,transfer, and deliver the semiconductor wafer 5.

The controller 70 is configured to control the operation of thesemiconductor wafer processing system 1. In some embodiments, thecontroller 70 includes a computer integrated manufacturing (CIM) hostand is electrically connected to all elements of the semiconductor waferprocessing system 1. For example, the controller 70 is electricallyconnected to the pumping assembly 32, the valve 25 and the valves 312and 314 of the pressure adjusting module 30 and controls the operationof the pumping assembly 32, the valve 25 and the valves 312 and 314 ofthe pressure adjusting module 30.

In order to transfer the semiconductor wafer 5 into the load lockchamber 20, the exterior door 22 is opened, and the interior door 23 isclosed to isolate the load lock chamber 20 from other components of theprocessing apparatus 10. Afterwards, the semiconductor wafer 5 isinserted into the load lock chamber 20 through the exterior door 22 andplaced on the wafer stage 21. After the semiconductor wafer 5 is placedin the load lock chamber 20, the exterior door 22 is closed to isolatethe load lock chamber 20 from the interface module 40. As a result, anair-tight environment is maintained in the load lock chamber 20.

FIGS. 2A-2E show schematic diagrams of a semiconductor wafer processaccording to an embodiment of the disclosure. In some embodiments, themask 14 is patterned by a procedure including photoresist coating and ane-beam exposure. After the e-beam exposure process, the resist materialis further processed by a thermal baking process, referred to as a postexposure bake (PEB). Then, an inspection on the PEB process is followed.PR is a photoresist layer containing the resist material. TL is a targetlayer disposed over the substrate to be patterned according to thedisclosed processes.

During the afore-mentioned processes, debris particles 119 can bereleased by the pod, or during transportation, e-beam writing, baking,developer and/or inspection. In some embodiments, larger debrisparticles 119 a remain on a surface 120 of the mask 14, as shown inFIGS. 2B and 2C. As shown in FIG. 2C, the debris particles 119 ainterfere with subsequent processing, such as etching of the targetlayer TL. In other embodiments, smaller debris particles 119 b arespread out over the photoresist pattern and the target layer, as shownin FIGS. 2D and 2E. As shown in FIG. 2E, the debris particles 119 binterfere with subsequent processing, such as etching of the targetlayer. Photoresist rework to remove debris particles requires much timefor photoresist re-coating and e-beam exposure. About 10˜33 additionalhours may be required to rework the photoresist. Proceeding with thedevelopment and etching operations with the particles present mayproduce defects.

FIG. 3 shows an embodiment for removing debris particles. The debrisparticles 119 c are a metal particle, a resist particle or a particle ofany material generally used in semiconductor manufacturing process suchas, for example, silicon dioxide, silicon nitride, etc. Depending on thetype of material and size of the debris particles 119 c, the debrisparticles 119 c adhere to the surface of the photoresist layer PR withvarying adhesive forces.

The debris particles could be removed using a stick with a glue.However, a gap between the stick and the photoresist layer PR would bean issue because the gap is hard to control, and the debris particlesmay fall back on the patterning side of the mask. In some cases, thedebris particles could be removed using an Atomic Force Microscopy(AFM). However, the process speed is slow for this method and the debrisparticles may fall back on the patterning side of the mask. The debrisparticles could be removed using a wind blade with a nozzle blowing aironto the patterning side with the mask facing up. However, the blowingair may cause the debris particles to spread out on the surface of themask during the removal operation. Alternatively, debris particles couldbe removed using a vacuum with the patterning side of the mask facingup. However, the debris particles may fall back on the mask.

The method shown in FIG. 3 removes the debris particles 119 c with thepatterning side of the mask facing down such that debris particles donot spread out on the patterning side of the mask or fall back on themask during the removal operation. The combination of the wind blade andvacuum process enhances the efficiency of the particles removal. Inaddition, there is no need to precisely locate the coordinate of debrisparticles because the full mask region can be processed. The debrisparticles can be removed without impacting photoresist quality.

As shown in FIGS. 4A and 4B, the particle cleaning assembly 1000includes a chuck assembly 1020, a holding and flipping member 1040 and aparticle removing cassette 1060. The chuck assembly 1020 holds the mask14 on which the debris particles are disposed.

Referring to FIGS. 5A and 5B, the photolithographic apparatus 100according to the present disclosure includes the particle removingcassette 1060 selectively extendable from the processing apparatus 10.In some embodiments, a wind blade slit 1100 includes an elongated windblade nozzle 1120 and an exhausting slit 1200 including an elongatedexhaust line 1220. FIG. 5A is an isometric view of the particle removingcassette 1060 and FIG. 5B is a cross section view of the particleremoving cassette 1060.

As also shown in FIGS. 6A and 6B, the particle removing cassette 1060includes a wind blade slit 1100 and an exhausting slit 1200 from whichpressurized cleaning material 1080 are introduced onto a surface 120 ofthe mask 14 to remove the debris particles 119 from the surface 120 ofthe mask 14. In some embodiments, the wind blade slit 1100 includes anarray of wind blade nozzles 1130 spaced apart within the wind blade slit1100, as shown in FIG. 6A. In some embodiments, a diameter of a windblade nozzle is in a range of about 0.3 to about 0.5 cm. In someembodiments, a distance between the wind blade nozzles of the array ofwind blade nozzles 1130 is in a range of about 0.5 to about 1 cm. Insome embodiments, the exhausting slit 1200 includes an array of exhaustlines 1230 spaced apart within the exhausting slit 1200. The elongatedwind blade nozzle 1120 is configured to direct pressurized cleaningmaterial 1080 to a surface 120 of the mask 14 to remove the debrisparticles 119 from the surface 120 of the mask 14. In some embodiments,the pressure of the pressurized cleaning material 1080 is in a range ofabout 0.3 to about 0.6 Pascal. In some embodiments, a flow rate of thepressurized cleaning material 1080 is in a range of about 15 to about 50liters per minute (LPM). The elongated exhaust line 1220 collects thedebris particles 119 and contaminants separated from the surface 120 ofthe mask 14 through the exhaust line 1220. In some embodiments, adistance between the particle removing cassette and a patterning surfaceof the mask is in a range from 0.8 mm to 1.2 mm. In some embodiments, adistance between the wind blade slit and the exhaust slit is in a rangefrom 8 mm to 12 mm.

With respect to FIG. 7, in some embodiments, the wind blade slit 1100further includes a pulsation insert 1160 inserted into the wind bladeslit 1100, and a directional positioner 1170. The pulsation insert 1160is configured to generate a pulsation/oscillation of the pressurizedcleaning material 1080. The directional positioner 1170 is configured tochange a two-dimensional direction and/or three-dimensional rotation ofthe pressurized cleaning material 1080. The directional positioner 1170is inserted in the wind blade slit 1100 and pops up from the particleremoving cassette 1060 when needed and is substantially concealed withinthe particle removing cassette 1060 when not in use. A controller 70selectively enables an adjustable angle portion of the directionalpositioner 1170 in some embodiments. The adjustable angle portionincludes a body that is slideably received within the processingapparatus 10 and has an inwardly projecting annular flange which bearsagainst any appropriate type of sealing.

In certain embodiments, the directional positioner 1170 is a 3-axisrotational device, and as it rotates in a certain direction, the windblade slit 1100 attached to the directional positioner 1170 is moved toa cleaning position.

In some embodiments, the controller 70 is configured to monitor debrisparticles 119 on the mask by a monitoring device 1420, adjust a flow anda pressure of the pressurized cleaning material by the pump when anamount of debris particles 119 in the mask is more than a thresholdamount or greater than a threshold size, and regulate ejectingparameters of the cleaning material, such as nitrogen, by operating acompressor and the pump when the pressurized nitrogen is ejected fromthe wind blade slit. In some embodiments, the monitoring device is acamera. In some embodiments, the ejection of the pressurized nitrogenfrom the wind blade slit is stopped when the monitoring device detectsthe amount of the debris particles on the mask is below the thresholdamount. Any appropriate controlling configuration regarding automaticand/or manual operation is contemplated and is not limited in thisregard. In some embodiments, the cleaning material includes nitrogen andother inert gases such as argon.

The cleaning position of the particle removing cassette with respect tothe surface 120 of the mask 14 is programmed by the controller 70according to different cleaning modes. For example, the cleaningposition may be programmed in a horizontal configuration relative to theprocessing apparatus 10. After positioning the wind blade slit 1100 tothe cleaning position (e.g., the horizontal configuration relative tothe processing apparatus 10), the directional positioner 1170 stopsmoving. The pressurized cleaning material 1080 then cleans the mask 14until the end of a cleaning time 1070.

As shown in FIG. 8, the supporting member 1300 includes an air inlet1320, a cleaning material inlet 1330, a mixer 1340, a compressor 1380and a pump 1390. The compressor 1380 pressurizes air taken in from theair inlet 1320. In some embodiments, the inlets 1320, 1330 and thecompressor 1380 are located outside of the processing apparatus.

In some embodiments, the particle removing assembly 1000 furtherincludes the pump 1390 for mixing cleaning material 1082 and thepressurized air stream 1084. The pressurized cleaning material 1080 isejected from the particle removing assembly 1000, i.e., the wind bladeslit 1100, and directed at the mask surface 120. In some embodiments,the pressure of the pressurized cleaning material 1080 is in a range ofabout 0.3 to about 0.6 Pascal. In some embodiments, a flow rate of thepressurized cleaning material 1080 is in a range of about 15 to about 50liters per minute (LPM).

The mixer 1340 transports the pressurized cleaning material 1080 via atransfer port 1360 to the wind blade slit 1100. In this cleaningprocedure, the wind blade slit 1100 directs the pressurized cleaningmaterial 1080 to the surface 120 of the mask 14 and microscopic shockwaves are generated by the cleaning material 1082 causing the debrisparticles 119 to be removed from the surface 120 of the mask 14. Theexhausting slit 1200 collects the debris particles 119 separated fromthe surface 120 of the mask 14 and the contaminants through an exhaustline 1220. Thereby, the cleaning effect is further enhanced by themicroscopic shock waves, and contamination inside the processingapparatus 10 is reduced in some embodiments.

FIGS. 9A-9H show a method of cleaning the mask for an photolithographicapparatus according to an embodiment of the disclosure. FIGS. 9A, 9B,9C, 9D, 9E, 9G and 9H are cross section views of the photolithographicapparatus and FIG. 9F is a plan view of the photolithographic apparatus.An exemplary cleaning procedure according to embodiments of thedisclosure is as follows: in operation S1001 as shown in FIG. 9A, theelectrostatic chuck 1022 of the chuck assembly 1020 holds the mask 14where the debris particles 119 are disposed thereon. In operation S1002as shown in FIG. 9B, the chuck assembly 1020 transports the mask 14 to acleaning location by lifting the mask 14 up. In operation S1003 as shownin FIG. 9C, the flipper 1042 of the holding and flipping member 1040catches and holds the mask 14. In operation S1004 as shown in FIG. 9D,the chuck assembly 1020 moves down. In operation S1005 as shown in FIG.9E, the flipper 1042 of the holding and flipping member 1040 flips themask 14 so that the mask 14 is facing downwards. FIG. 9F is a plan viewshowing two holding and flipping members 1040 securing the mask 14 inoperation S1006. In operation S1007 as shown in FIG. 9G, the particleremoving cassette 1060 extends from the processing apparatus 10 to bepositioned in the debris removing location. In operation S1008 as shownin FIG. 9H, the debris particles are removed from the mask 14 by theparticle removing cassette 1060 using pressurized cleaning material anda vacuum according to the embodiments disclosed herein.

Embodiments of the present disclosure provide cleaner masks with reducedcontamination. Embodiments of the present disclosure further provide thebenefit of reducing downtime during maintenance and servicingphotolithographic tools and masks. The design of the cleaning system andparticle removing cassette allows for faster maintenance with reducedservicing time. The adaptation of the cleaning system allows an improvedprocess resulting in reduced manpower required to perform themaintenance, and an increased output of conforming servicing items ofthe photolithographic tools—both of which ultimately result in acost-savings. As such, the photolithographic tools and masks are moreefficiently used. However, it will be understood that not all advantageshave been necessarily discussed herein, no particular advantage isrequired for all embodiments or examples, and other embodiments orexamples may offer different advantages.

An embodiment of the disclosure is a method of cleaning a mask for aphotolithographic apparatus, in which the photolithographic apparatuscomprises a particle removing cassette that is selectively extendablefrom the photolithographic apparatus and having a wind blade slit, anexhaust slit and a supporting member. First, a patterning surface of themask is positioned facing down along a direction of gravity.Subsequently, the method ejects the pressurized cleaning material fromthe supporting member through the wind blade slit toward debrisparticles on the patterning surface of the mask. The method then removesthe debris particles from the mask. Finally, the method collects thedebris particles and contaminants. In some embodiments, the cleaningmethod includes positioning the wind blade slit with respect to thedebris particles by an extendable positioner. In some embodiments, thecleaning method oscillates the pressure of the pressurized nitrogen. Insome embodiments, the cleaning method monitors the debris particles onthe mask. In such embodiments, the method then adjusts a flow and apressure of the pressurized cleaning material by a pump and a compressorwhen an amount of the debris particles in the mask is more than athreshold amount or greater than a threshold size. In such embodiments,the method regulates the operating parameters of the pump and thecompressor. In some embodiments, a pulsation insert is inserted into thewind blade slit to generate a pulsation of the pressurized cleaningmaterial. In some embodiments, an directional positioner is insertedinto the wind blade slit to change a three-dimensional rotation of thepressurized cleaning material. In some embodiments, a distance betweenthe particle removing cassette and the patterning surface of the mask isin a range from 0.8 mm to 1.2 mm. In some embodiments, a distancebetween the wind blade slit and the exhaust slit is in a range from 8 mmto 12 mm.

Another embodiment of the disclosure is a cleaning system for aphotolithographic apparatus that includes a mask, a particle removingcassette and a chamber enclosing the mask and the particle removingcassette and a controller communicating with the particle removingcassette. The particle removing cassette includes a blowing device, anexhausting device, and a supporting device. In some embodiments, theparticle removing cassette includes a monitoring device for monitoringdebris particles on the mask. In some embodiments, the blowing deviceincludes an air inlet, a nitrogen inlet, a mixer and a wind blade slit.In some embodiments, the wind blade slit includes a pulsation insert anda directional insert. In some embodiments, the supporting memberincludes a compressor. In some embodiments, the supporting memberincludes a pump. In some embodiments, the blowing member includes anextendable positioner. In some embodiments, the photolithographicapparatus includes a controller configured to monitor debris particleson a surface of the mask. In such embodiment, the photolithographicapparatus then adjusts a flow and a pressure of the pressurized cleaningmaterial by the pump when an amount of the debris particles in the maskis more than a threshold amount or greater than a threshold size. Insuch embodiment, the photolithographic apparatus finally regulatesejecting parameters of the compressor and the pump, when pressurizedcleaning material is ejected from the wind blade slit. In someembodiments, a distance between the particle removing cassette and thepatterning surface of the mask is in a range from 0.8 mm to 1.2 mm.

Another embodiment of the disclosure is a method of cleaning a mask fora photolithographic apparatus. The method first provides a mask within achamber. The method then provides a particle removing cassette having awind blade slit, an exhaust slit and a supporting member inside thechamber. Then method then forms pressurized cleaning material includingnitrogen and a pressurized air stream from the supporting member. Then,the method ejects the pressurized cleaning material through an array ofwind blade nozzles spaced apart within the wind blade slit toward thedebris particles at the patterning surface of the mask. The methodremoves the debris particles from the mask, and finally, collects thedebris particles and contaminants by an array of exhaust lines spacedapart within the exhausting slit. In some embodiments, the cleaningmethod further regulates the cleaning using a controller. In suchembodiment, the controller is configured to monitor the debris particleson the mask, and compare an amount of the debris particles on the maskwith a threshold amount to remove the debris particles by thepressurized cleaning material. In some embodiments, the cleaning methodstops the ejecting the pressurized cleaning material when the amount ofthe debris particles on the mask is below the threshold amount.

The foregoing outlines features of several embodiments or examples sothat those skilled in the art may better understand the aspects of thepresent disclosure. Those skilled in the art should appreciate that theymay readily use the present disclosure as a basis for designing ormodifying other processes and structures for carrying out the samepurposes and/or achieving the same advantages of the embodiments orexamples introduced herein. Those skilled in the art should also realizethat such equivalent constructions do not depart from the spirit andscope of the present disclosure, and that they may make various changes,substitutions, and alterations herein without departing from the spiritand scope of the present disclosure.

What is claimed is:
 1. A cleaning method of a mask for aphotolithographic apparatus, wherein the photolithographic apparatuscomprises: a particle removing cassette having a first slit and anelongated wind blade nozzle extending along a length of the first slitand protruding from the first slit; and the method comprising: ejectingpressurized cleaning material through the elongated wind blade nozzle ofthe first slit toward debris particles on a patterning surface of themask to remove the debris particles from the patterning surface of themask.
 2. The cleaning method of claim 1, further comprising: positioningthe elongated wind blade nozzle with respect to the debris particles byan extendable positioner.
 3. The cleaning method of claim 1, furthercomprising: monitoring an amount of the debris particles on thepatterning surface of the mask; adjusting a flow rate and a pressure ofthe pressurized cleaning material by a pump and a compressor based onthe amount of the debris particles on the patterning surface of themask; and regulating operating parameters of the pump and the compressorbased on the amount of the debris particles on the patterning surface ofthe mask.
 4. The cleaning method of claim 1, further comprising:three-dimensionally rotating the pressurized cleaning material ejectedfrom the elongated wind blade nozzle of the first slit using adirectional positioner inserted into the first slit; and directing, bythe rotating, the pressurized cleaning material to one or more debrisparticles on the patterning surface of the mask.
 5. The cleaning methodof claim 4, wherein the particle removing cassette further comprises anelongated exhaust line extending along a length of a second slit, themethod further comprising: collecting the debris particles removed fromthe patterning surface of the mask by the elongated exhaust line of thesecond slit.
 6. The cleaning method of claim 1, further comprising:positioning the patterning surface of the mask facing down along adirection of gravity.
 7. A photolithographic apparatus, comprising: aparticle removing cassette, wherein the particle removing cassettecomprises: a first slit; an array of two or more parallel wind bladenozzles arranged along a length of the first slit; and a supportingmember coupled to the particle removing cassette and configured to ejectpressurized cleaning material from the supporting member through thearray of two or more parallel wind blade nozzles and direct thepressurized cleaning material to a patterning surface of a mask.
 8. Thephotolithographic apparatus of claim 7, further comprising: a maskholder and a mask, wherein the mask is mounted in the mask holder with apatterning surface of the mask facing down along a direction of gravity;and a monitoring device for determining an amount and a size of debrisparticles on the patterning surface of the mask.
 9. Thephotolithographic apparatus of the claim 8, further comprising acontroller, wherein the supporting member further comprises a pump, thecontroller is configured to: monitor the determined amount and the sizeof the debris particles on the patterning surface of the mask, adjust aflow rate and a pressure of the pressurized cleaning material by thepump based on the amount and the size of the debris particles on thepatterning surface of the mask, and regulate ejecting parameters of thepump when the pressurized cleaning material is ejected from the array oftwo or more parallel wind blade nozzles.
 10. The photolithographicapparatus of claim 8, wherein a distance between the particle removingcassette and the patterning surface of the mask is in a range from 0.8mm to 1.2 mm.
 11. The photolithographic apparatus of claim 8, furthercomprising: a pulsation insert mounted in the first slit and configuredto oscillate a pressure of the ejected pressurized cleaning material;and a directional positioner mounted in the first slit and configured toprovide a three-dimensional rotation of the ejected pressurized cleaningmaterial.
 12. The photolithographic apparatus of claim 8, wherein thearray of two or more parallel wind blade nozzles protrudes out of theparticle removing cassette toward the patterning surface of the mask.13. The photolithographic apparatus of claim 11, wherein the directionalpositioner is configured to move the array of two or more parallel windblade nozzles to direct the ejected pressurized cleaning material towardthe debris particles and contaminations on the patterning surface of themask.
 14. The photolithographic apparatus of claim 7, wherein the arrayof two or more parallel wind blade nozzles comprises between 5 to 7nozzles.
 15. The photolithographic apparatus of claim 8, furthercomprising: an extendable positioner coupled to the particle removingcassette and configured to move the array of two or more parallel windblade nozzles with respect to the debris particles on the patterningsurface of the mask.
 16. A cleaning method of a mask in a chamber of aphotolithographic apparatus having a particle removing cassette thatcomprises first and second slits, the method comprising: ejecting apressurized cleaning material through the first slit toward debrisparticles and contaminations on a patterning surface of the mask toremove the debris particles and the contaminations; and collecting thedebris particles and the contaminants removed from the patterningsurface of the mask by an elongated exhaust line extending along alength of the second slit and protruding from the second slit.
 17. Thecleaning method of claim 16, further comprising: regulating the cleaningusing a controller to: monitor an amount of the debris particles on thepatterning surface of the mask, and adjust a flow rate of the ejectedpressurized cleaning material based on the monitored amount of thedebris particles on the patterning surface of the mask.
 18. The cleaningmethod of claim 17, further comprising: stopping the ejecting thepressurized cleaning material when the amount of the debris particles onthe patterning surface of the mask is below a threshold amount.
 19. Thecleaning method of claim 16, wherein an elongated wind blade nozzlearranged along a length of the first slit, the method furthercomprising: oscillating a pressure of the pressurized cleaning materialejected from the elongated wind blade nozzle of the first slit.
 20. Thecleaning method of claim 19, further comprising: generating a pulsationof the pressurized cleaning material ejected from the elongated windblade nozzle of the first slit using a pulsation insert that is insertedin the first slit.